1. Field of the Invention
The present invention relates to a cellular phone which has an electronic mail transmission/reception function and a schedule registration function and to a method of using the cellular phone.
2. Description of the Related Art
A cellular phone has been widely used in various situations which includes a specific situation such that a bearer or a holder of the cellular phone can not immediately respond to an incoming call to talk to a sender or caller. Practically, using the cellular phone is often restrained, for example, during a meeting, boarding of public transportation, and seeing of movies in a movie theater. In order to cope with this restraint, a message recording and answering service (simply called an answering service) is well known in the art as a cellular phone service. With this cellular phone service, a sender's voice is recorded as a message in a receiver's cellular phone which is subject to the above-mentioned answering service and the receiver can reproduce the sender's voice later to know who the sender is and what he/she is requested.
However, the sender's request or errand can rarely be accomplished only when the sender's message is recorded/ left in the receiver's cellular phone in one-way communication alone. Therefore, the sender leaves a message of requesting the receiver to call back to the sender in many cases. Under the circumstances, the receiver should very often call back to the sender in accordance with the recorded message left in the receiver's cellular phone. Otherwise, the sender should call back to the receiver again.
At any rate, the sender can not know the reason why no response can be received from the receiver and also can not judge when next calling should be made. Therefore, the sender sometimes makes many calls, or loses a chance to make a contact with the receiver.
When the receiver is subjected to the answering service, the sender of the phone call pays a charge for the phone call, in spite of the fact that any practical communication cannot be made.
Recent cellular phones have been generally equipped with a computer or a micro processor so as to transmit/receive electronic mails (often abbreviated to e-mails) and to process various information. Such a cellular phones is exemplified in Document 1 (Japanese Unexamined Patent Publication No. 2002-51378). The cellular phone disclosed in Document D1 can automatically send an e-mail to a sender or a receiver of a phone call by the use of the e-mail function, after no response can be obtained from the receiver. Such an e-mail includes a predetermined message. Another cellular phone is described in Document 2 (Japanese Unexamined Patent Publication No. Hei 8-331621) which is linked with a schedule registration function installed in the cellular phone. Specifically, the cellular phone disclosed in Document D2 receives an incoming call and/or an incoming e-mail and automatically transmits, from a receiver, a message peculiar to the incoming call or e-mail when the receiver cannot respond to the incoming call or e-mail. In this event, such a peculiar message may be related to a receiver's schedule installed in the receivers cellular phone and may indicate that the receiver is in a meeting or the like.
Moreover, related arts are also disclosed in Documents 3 and 4 (Japanese Unexamined Patent Publication Nos. 2002-269214 and 2002-288394). In Documents D3 and D4, schedule management systems have been proposed which use cellular phones or portable terminals, such as PDA (Personal Digital Assistance). In these systems, not only a system owner but also a business manager and the like can refer to the schedule through a network by using the cellular phones and/or the portable terminals.
Herein, it is to be noted in Documents 1 and 2 that, when a sender makes a telephone call to a receiver subjected to the answering service and the receiver cannot make any response to the telephone call, there is a problem that an unnecessary charge for the telephone call is imposed on the sender. In addition, the sender cannot know when the receiver can make a response, and therefore eventually repeats calling to the receiver many times. Otherwise, the sender might not communicate with the receiver.
On the other hand, using the schedule management system described in Documents 3 and 4 may make it possible to refer to a schedule of a receiver from the sender and to predict a time when the receiver can make a response. However, the schedule management system needs a control system that is constituted separately from the cellular phone system. Thus, a user has to separately make access to the control system. Taking protection of secrecy or privacy into consideration, the schedule management system can not be easily used in a case other than a limited case where the schedule management system is used between a business supervisor and a subordinate during a business hour.